From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A4EFFF30942 for ; Thu, 5 Mar 2026 11:08:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=qsAq/tvmOCsJjNyt6pk4vJn17T4gSc6sHLColuljBUc=; b=D5CE/0AJvTclz5 UwkqgKzcIYHMohBo3AURv8e6u1XoITASUxyFKugvU6rH267xKwyPlqVHE2XIVk4l2+e21DwEEBwUB vG0ougIImf1A/vV/VAaZY6v4ZEV2FlQqMPa/l2QTpgld3xE9Drv6XAUdOCyus6VmUaReJR1dvgN0M lt9AXWJF+PrLtqcyrsTbCGVrFeO+yl/iDg4HhtruUbA9Ayi6qyi+kcaU+SkR798TpR6pRg2I9dJhn WDpnXtTmuaY5dHCnpG/lgH+v4yvMVrT1PtaUqQIjH4aO1yw43Y3hugtfxcTaU0al0cUjd0ITtjLvZ jcjPJd+2S+deEQAFYQAQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vy6Za-00000001ekQ-0kuv; Thu, 05 Mar 2026 11:08:54 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vy6ZX-00000001ek2-0jUA; Thu, 05 Mar 2026 11:08:52 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id CCB7341A10; Thu, 5 Mar 2026 11:08:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0367DC116C6; Thu, 5 Mar 2026 11:08:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772708930; bh=tTMMEC8DuOg1OgtIV4CsJVix0a9ND4jTsqpfaC+txgU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=jtg7009ZtZSI6coaiefM/RbQhyka7Oddg3/RpS89UF2GUuMQfeee5xtOnlV3OVe1+ j2CIFx7FZDW2p5iqSVXnD0kBr+WuARETGom1gAnd42Q9LuC+G2J9YKTb5nYCT4dyic T/udTT4Sj3sJvhxuxT0eejT71mBhE85fP/8v+YruYHB+56VXNiheMIOeErbIwSLNG4 rfNnTFKHvXlpjREcGYZJs2TZ9Ql5i6xIsNLbQ9GLa5mVJvxMWFipI4wYA0v7hqXHIo 2pWt4rNYNksUCzAQ+sN0ab2/jVzOZwGBw/kADMgaCnK6TsYwWsbwE6uxTwYyEz0iXQ CY60NCcv3jtUw== Message-ID: <69900d76-3820-467a-9fbc-13f79189df2f@kernel.org> Date: Thu, 5 Mar 2026 12:08:43 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v4 1/4] media: dt-bindings: Add Amlogic V4L2 video decoder To: Zhentao Guo , Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Neil Armstrong , Kevin Hilman , Jerome Brunet , Martin Blumenstingl Cc: linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org References: <20260213-b4-s4-vdec-upstream-v4-0-c7112d00d662@amlogic.com> <20260213-b4-s4-vdec-upstream-v4-1-c7112d00d662@amlogic.com> <75e55ceb-e6dd-47b5-a829-66f6fbb3e13e@amlogic.com> <2f68ee18-e9d9-4da6-900c-93a7663b3c9d@kernel.org> <598c161c-d157-40e5-992c-912540589d7e@amlogic.com> <58d57a6c-7c69-4f5b-a4c2-f34ef0238511@kernel.org> <26d0f52e-3681-46ce-b0dc-0cb020e8d9a1@amlogic.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org On 05/03/2026 12:01, Zhentao Guo wrote: > > 2. Why canvas is needed? > > 1. Since the ARM IOMMU HW is not integrated into the Amlogic SOCs,we > need canvas to prevent the DDR memory used by the decoder from being > rewrote by other hardware. Canvas provides the decoder with a > configurable DDR memory range, as well as hardware-based detection > and blocking for out-of-bounds access. > 2. From the diagram above, we can see a lite CPU called AMRISC. AMRISC > is the controller of the decoder HW and the decoder driver needs to > access the decoder hardware through AMRISC. However, AMRISC is a > 16-bit CPU and cannot directly handle 32-bit or 64-bit physical > addresses. Therefore, canvas is required to convert the addresses > into index to facilitate processing by the AMRISC core. This suggests "Canvas" is IOMMU, thus use proper IOMMU abstractions and you cannot have own phandle for it. Best regards, Krzysztof _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic